Overwhelming Critical Range?

[Nitesco]

Overwhelming Critical adds +1 to the critical damage multiplier on a 19-20. Does this automatically grant the weapon you are using a critical hit on a 19, even if it normally would only crit on a 20? How will this affect the Improved Critical feat? Or the Kensai III Prestige Enhancement?

[Dwarfo]

I think you need Improved Critical to take this feat.

[Nitesco]

I think you need Improved Critical to take this feat.

Yes you are right.